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Red-spotted Purple

Limenitis arthemis astyanax[3]

The red-spotted purple is a black butterfly with iridescent blue hind wings, common in wooded suburbs; its caterpillars look like bird droppings and feed harmlessly on cherry, willow, apple and other trees.[1][2]

Group
Insect
Order
Lepidoptera
Family
Nymphalidae
US records
37 states
Sources
3 cited
Updated
2026-10-15
Blue-black red-spotted purple butterfly with iridescent blue hind wings
Blue-black red-spotted purple butterfly with iridescent blue hind wings. (c) northerly, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Adults span about 3 to 3 1/2 inches: black forewings with small white and orange spots and black hind wings with iridescent blue patches.[1]
  • Caterpillars are about 1 1/2 inches, mottled white, green and brown like a bird dropping, with a pair of large barbed horns behind the head.[1][2]

Look-alikes

Look-alikeHow to tell them apart
Pipevine swallowtailIt is considered a mimic of the poisonous pipevine swallowtail, which shares its range.[1]

Where it lives

A forest butterfly also common in wooded suburban areas; MU Extension reports caterpillars from early summer to fall.[1][2]

US map: public records from 37 states since 1990 (GBIF).

Biology and life cycle

There are two generations a year; young caterpillars eat the leaf tip and rest on a 'frass spar' extended from the midrib.[1][2]

Damage and signs

  • Hosts include willow, apple, wild cherry, wild crab, elm and oak; feeding is not a concern.[2]

Health risk

None to people or pets.[1][2]

Control

Prevention

No control is needed.[1][2]

Common questions

What is the black butterfly with blue wings in my yard?
Possibly a red-spotted purple.[1]
Why does the caterpillar look like bird poop?
Its mottled pattern is camouflage that resembles a bird dropping.[2]
Is it a pest?
No.[1][2]

Sources

  1. University of Florida IFAS Extension (EDIS, Featured Creatures), “Red-Spotted Purple, Limenitis arthemis astyanax (EENY-447/IN814).” ask.ifas.ufl.edu/publication/IN814 (accessed 2026-10-15)
  2. University of Missouri Extension (Caterpillars in Your Yard and Garden, IPM1019), “Caterpillars in Your Yard and Garden, page 36: Red-spotted purple.” extension.missouri.edu/publications/ipm1019-36 (accessed 2026-10-15)
  3. iNaturalist, “Limenitis arthemis taxon page (order and family).” www.inaturalist.org/taxa/60607 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.